The James Webb Space Telescope will soon turn its eyes to the king of the solar system, gas giant Jupiter.
Jupiter is a complex system full of mysteries, hosting worlds of questions regarding the nature of its delicate rings, how its largest moons can harbor oceans of water or hidden volcanoes, and how massive storms like the Great Red Spot form in the giant planet’s turbulent atmosphere. Researchers say the planet will be the perfect “testing ground” for the James Webb Space Telescope, the $10 billion observatory that will display its first operational images on July 12.
“It’s going to be a really challenging experiment,” study co-author Emke de Pater, a planetary scientist at UCLA, said of Webb’s upcoming studies of Jupiter in a 2020 consortium statement. (Opens in a new tab).
Added de Pater, who is leading the study with Thierry Foucher of the Observatoire de Paris.
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Jupiter is a bright target that will require careful calibration of Webb’s instruments, so as not to wash the planet in the telescope’s sensitive optics. The gas giant also rotates quickly, which makes it difficult to take a time-lapse photo for scientific observations.
But once those hurdles are overcome, the scientists say they’re looking forward to new insights using Webb’s unique 18-segment mirror and four infrared instruments.
Studies of Jupiter’s atmosphere will feature prominently. For example, the telescope will study mysterious hurricane storms in the polar region, which are also under scrutiny by NASA’s Juno spacecraft, to look at winds, clouds, gas and temperature.
Webb will also look at the atmosphere just above the swirling Great Red Spot, which contains unexplained temperature changes (for example, the atmosphere above Jupiter is much cooler than other regions of Jupiter).
Beyond that, the team hopes to discover new moons in Jupiter’s rings. This would be particularly difficult because the planet’s bright light could wash out a system of faint rings made up of small, scattered dust particles, officials said. (Strategies for dealing with this problem could help future exoplanet observers by using Webb to see faint worlds next to bright stars.)
Then there are Jupiter’s large moons. This first set of studies will examine Ganymede glacial and volcanic Io to gain more insights into how these worlds have formed and changed over time.
The researchers stated that Ganymede’s outer atmosphere will be imaged by Webb “to better understand the moon’s interaction with particles in Jupiter’s magnetic field.” Webb will also search for a suspected saltwater ocean below Ganymede’s surface.
Io’s investigations will include searching for “hidden volcanoes,” which researchers suspect erupt without scattering any dust particles that would better reflect light for telescopes to see.
However, Webb has a higher spatial resolution than previous missions to Jupiter (including Voyager and Galileo), which allows him to observe ghost volcanoes along with “hot spots”. The concentrations of elevated temperatures on Io’s surface may be similar to what we see in volcanoes on Earth, but more study is needed to confirm observations made by Galileo in the 1990s and 2000s.
The statement said the telescope will also look in detail at Io’s temperature structure, which is relatively unknown so far since not much data has been collected about temperature at different altitudes from the lunar atmosphere.
As Webb directs his optics at Jupiter from deep space, observatories orbiting near the planet will provide assistance. For example, it will provide Webb’s long-range view of Jupiter’s atmosphere and valuable context for Juno’s orbiting Jupiter.
“No observatory or spacecraft can do everything,” study co-author Michael Wong of the University of California, Berkeley, said in the same statement. “We are very excited about collecting data from several observatories to tell us so much more than we can learn from just one source.”